Added MessageMapper strategy interface and simple implementation.

spring-eai-core/src/main/java/org/springframework/integration/message/MessageMapper.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2002-2007 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.message;
+
+/**
+ * Strategy interface for mapping between messages and objects.
+ * 
+ * @author Mark Fisher
+ */
+public interface MessageMapper {
+
+	/**
+	 * Map to a {@link Message} from the given object.
+	 */
+	Message toMessage(Object source);
+
+	/**
+	 * Map from the given {@link Message} to an object.
+	 */
+	Object fromMessage(Message message);
+
+}

spring-eai-core/src/main/java/org/springframework/integration/message/SimplePayloadMessageMapper.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2002-2007 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.message;
+
+import org.springframework.integration.util.RandomGuidUidGenerator;
+import org.springframework.integration.util.UidGenerator;
+import org.springframework.util.Assert;
+
+/**
+ * A {@link MessageMapper} implementation that simply wraps and unwraps a
+ * payload object in a {@link DocumentMessage}.
+ * 
+ * @author Mark Fisher
+ */
+public class SimplePayloadMessageMapper implements MessageMapper {
+
+	private UidGenerator uidGenerator;
+
+
+	/**
+	 * Create a mapper with the provided id generation strategy.
+	 * 
+	 * @param uidGenerator the generator to use for message ids
+	 */
+	public SimplePayloadMessageMapper(UidGenerator uidGenerator) {
+		Assert.notNull(uidGenerator, "uidGenerator must not be null");
+		this.uidGenerator = uidGenerator;
+	}
+
+	/**
+	 * Create a mapper with the default id generation strategy.
+	 * 
+	 * @see RandomGuidUidGenerator
+	 */
+	public SimplePayloadMessageMapper() {
+		this.uidGenerator = new RandomGuidUidGenerator();
+	}
+
+
+	/**
+	 * Return the payload of the given Message.
+	 */
+	public Object fromMessage(Message message) {
+		return message.getPayload();
+	}
+
+	/**
+	 * Return a {@link DocumentMessage} with the given object as its payload.
+	 */
+	public Message toMessage(Object source) {
+		return new DocumentMessage(uidGenerator.generateUid(), source);
+	}
+
+}